In the automobile industry, as general concerns about energy and environment are increased globally, the efficiency in each part including fuel efficiency has been steadily improved, and in order to satisfy various demands of customers, research and development on lighter weight, smaller size and multi-function of each vehicle component has been carried out. Particularly, in an air-conditioning unit for a vehicle, since it is generally difficult to secure an enough space in an engine room, it is required to manufacture an automobile air conditioner having a small size and high efficiency in controlling temperature and air flow.
In general, the automobile air conditioner is an apparatus for properly maintaining internal temperature of a vehicle during the summer and winter seasons, or removing frost formed on vehicle windows during rainy days or the winter season so as to secure a driver's visual field. The automobile air conditioner is configured so that external air introduced by a ventilator is passed through a heater core or an evaporator through which a refrigerant is flowed and then the cooled or heated air is distributed through vents communicated with various portions inside a vehicle.
FIG. 1 is a cross-sectional view of a conventional air conditioner of an automobile. As shown in FIG. 1, the conventional air conditioner includes an air-conditioning case 10 formed with a vent 11, 12, 13 of which an opening degree is controlled by a door 11d, 12d, 13d; a ventilator 14 which is connected with an air inlet port of the air-conditioning case 10 so as to ventilate external air; an evaporator E and a heater core H which are provided in the air-conditioning case 10; a temp door 15 which functions to control an opening degree of a cooled air passage P1 and a heated air passage P2 of the air-conditioning case 10.
As described above, in a cooling cycle of the conventional air conditioner, the temp door 15 opens the cooling air passage P1 and also closes the heated air passage P2. Therefore, the air ventilated by the ventilator 14 is converted into cooled air, while passing the evaporator E so as to be heat-exchanged with a refrigerant in the evaporator E, and flowed into the cooled air passage P1, and then discharged through the opened vent 11, 12, 13 so as to air-condition an inside of the vehicle.
Further, in a heating cycle, the temp door 15 closes the cooling air passage P1 and also opens the heated air passage P2. Therefore, the ventilated air is converted into heated air, while passing the heater core H so as to be heat-exchanged with a refrigerant in the heater core H, and flowed into the heated air passage P1, and then discharged through the opened vent 11, 12, 13 so as to heat the inside of the vehicle.
FIG. 2 is a perspective view of a conventional heater core H wherein two kinds of typical heater cores, i.e., a U-turn type heater core of FIG. 2a and a one-way type heater core are illustrated. As shown in FIG. 2, the conventional heater core H includes first and second heater tanks 21 and 22 which are disposed in parallel to be spaced apart from each other in a desired distance; inlet and outlet pipes 25 and 26 which are respectively connected with the first header tank 21 or the second header tank 22 and through which a heat exchange medium is introduced or discharged; a plurality of tubes 23 of which both ends are fixed between the first and second header tanks 21 and 23; and a fin 24 which is interposed between the tubes 23.
In FIGS. 1 and 2, the same reference numerals are designated to the same parts of an automobile air conditioner in which the conventional heater core or a heater core of the present invention is installed.
However, in the conventional automobile air conditioner, since the evaporator and the heater core are respectively fixed at particular positions and also it needs the temp door for controlling an opening degree of each of the cooled and heated air passages upon the air-conditioning and heating, it is necessary to secure a space in an engine room corresponding to a rotating radius of the temp door. Further, since its complicated structure interferes with air flow, it is difficult to obtain appropriate air volume, and also it generates a loud noise.
Furthermore, in the conventional heater core, since it is not possible to control an amount of the refrigerant which is introduced into the heater core, the high temperature refrigerant is continuously introduced into the heater core even in case of the cooling cycle. Thus, although the heated air passage is closed by the temp door so as to prevent the introduction of the heated air, air-conditioning efficiency is deteriorated by the high temperature refrigerant and the heated air.